In November 2021, 14 international travel-related severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) B.1.1.529 (omicron) variant of concern (VOC) patients were detected in South Korea. Epidemiologic investigation revealed community transmission of the omicron VOC. A total of 80 SARS-CoV-2 omicron VOC-positive patients were identified until December 10, 2021 and 66 of them reported no relation to the international travel. There may be more transmissions with this VOC in Korea than reported.
Here we report a novel approach to fabricate conical microstructures on aluminum substrates using a cost-effective and scalable hydrothermal synthesis method.
As the oxygen evolution reaction (OER) imposes a high energy barrier during electrochemical water splitting, designing highly efficient, stable, and cost-effective electrocatalysts for OERs is an ongoing challenge. In this study, we present a facile approach to prepare villi-shaped Ni−Fe hydroxides incorporated with oxalate derived from Ni−Fe oxalate through the in situ precipitation growth and subsequent immersion in an alkaline solution. The electrode with an optimized Ni−Fe ratio improves the OER kinetics, on which the electronic structure of the active site is adjusted based on a mutual effect between the adjacent nickel and iron atoms. The OER performance was significantly better than that of monometallic Ni(OH) 2 and pristine Ni foam, with a low overpotential of 277 mV at 100 mA cm −2 and excellent stability. The enhanced OER performance is ascribed to the advanced intrinsic electrocatalytic activity of the electrode as a result of the synergetic effect of optimized Ni−Fe ratio mixing at the atomic level which leads to an increased surface area, a high number of active sites, and a reduced charge transfer resistivity.
The adherence of underwater air bubbles
to surfaces is a serious
cause of malfunction in applications such as microfluidics, transport,
and space devices. However, realizing spontaneous and additional unpowered
transport of underwater air bubbles inside tubes remains challenging.
Although superhydrophilic polydimethylsiloxane (PDMS) tubes are attracting
attention as air bubble repellents, superhydrophilic PDMS, which is
fabricated via oxygen plasma treatment, has a disadvantage in that
it is weak against aging. Here, we present a tube with the ability
to self-remove air bubbles, which overcomes the drawback of rapid
aging. PDMS containing Silwet L-77 with a hierarchical nano–microstructure
exhibiting subaqueous aerophobicity was fabricated. We conducted adherence
and saturation experiments of air bubbles using the fabricated PDMS
tube with Silwet L-77 to investigate the mechanism of bubbles adhering
to and separating from the fabricated tube surface. The developed
PDMS with Silwet L-77 exhibits a strong self-removal effect with an
air bubble removal of 97.7%. The adherence and saturation experiments
suggest that the transparent superhydrophilic–underwater aerophobic
PDMS is a potentially exceptional tool for spontaneously separating
air bubbles attached to tube surfaces.
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